This invention relates to microelectronic devices, and, more particularly, to a packaging structure for multilayered microelectronic devices.
A major challenge in the design of complex electronic devices such as specialized computers and controllers is to provide ever-more-powerful and more-complex electronic circuitry in small, light packages. Great advances have been made in microelectronic fabrication that permit large numbers of circuit elements to be fabricated onto individual chips, which are in turn attached to a circuit board.
In one common architecture, the circuit elements are placed onto a number of circuit boards, due to reasons of manufacturing efficiency, electronic function and requirements, size and complexity, and ease and cost of replacement in the event of a failure of one of the electronic components. The circuit boards are disposed in parallel to each other and affixed to another board commonly termed a backplane or backplane board. The backplane has a pattern of thin metallic leads termed traces thereon to provide electrically connective paths between the adjacent circuit boards. Such a packaging architecture is found in most desk-top computers, for example.
For many applications, this architecture is fully satisfactory. In others, however, the long electrical path lengths between circuit elements on adjacent circuit boards, through the backplane board, result in slower-than-desired operating speeds. The long path lengths also produce higher power dissipation during high-speed operation.
Additionally, the electronic components on the circuit boards generate heat during operation, which must be conducted away to avoid overheating. The removal of heat may be the limiting consideration in reducing the size and weight of the electronic device, especially in those cases where the electronic device utilizes a good deal of power or processes high-frequency signals. Most commonly, the heat may be dissipated by forcing air to flow between the circuit boards to absorb the heat, and thereafter carry the heat away through a ventilation grill. In some situations this approach is not feasible, as for example where the entire electronic device is hermetically sealed within an enclosure. In that case and in others for reasons of cooling efficiency, the heat is conducted away by metallic conductors or heat pipes that extend to the circuit boards at one end and a radiator or other heat sink at the other. The removal of heat by such known approaches is operable, but adds greatly to the size and weight of the electronic device.
There is a need for an improved approach for the architecture and structure of microelectronic packaging applications to overcome these problems. The present invention fulfills this need, and further provides related advantages.